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Can I write useful perl programs on the command li



Jasmine
Administrator

Jan 19, 2001, 12:15 PM


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Can I write useful perl programs on the command li

(From the Perl FAQ)

Can I write useful perl programs on the command line?

Yes. Read the perlrun manpage for more information. Some examples follow. (These assume standard Unix shell quoting rules.)

Code
    # sum first and last fields 
perl -lane 'print $F[0] + $F[-1]' *

# identify text files
perl -le 'for(@ARGV) {print if -f && -T _}' *

# remove (most) comments from C program
perl -0777 -pe 's{/\*.*?\*/}{}gs' foo.c

# make file a month younger than today, defeating reaper daemons
perl -e '$X=24*60*60; utime(time(),time() + 30 * $X,@ARGV)' *

# find first unused uid
perl -le '$i++ while getpwuid($i); print $i'

# display reasonable manpath
echo $PATH | perl -nl -072 -e '
s![^/+]*$!man!&&-d&&!$s{$_}++&&push@m,$_;END{print"@m"}'

Ok, the last one was actually an obfuscated perl entry. :-)